Such products typically comprise an absorbent core of porous material which can absorb and retain a large quantity of fluid. The core can be regarded as having a top face intended to face the body of the user, and a back face intended to face the external environment. The absorbent core almost always has a sheet which covers the top face, and is referred conventionally and herein as a topsheet, and generally, though not always, it has a further coversheet which covers the back face and is referred to conventionally and herein as a backsheet. The topsheet must be fluid-permeable, to allow body fluids to pass therethrough into the absorbent core. For this purpose it is known, for example to provide perforations in the topsheet. The present invention is concerned with a novel form of topsheet.
Until recent years, all, or at least substantially all, absorbent products for sanitary use were substantially or wholly inelastic. However, in more recent times it has been appreciated that it would be advantageous for at least some types of absorbent sanitary product to be elastic. Our copending application entitled "Absorbent Sanitary Article", application TO94A000797 IT, filed on the same date as the present application, describes one such absorbent product, the preferred embodiments of which are in the form of pantiliners.
One of the problems which can arise in constructing such an absorbent product is in the provision of a suitable topsheet. At least in some forms of elastic absorbent product the topsheet itself may need to be elastic, and it is believed that at present no suitable elastic topsheets are available. It is an object of the present invention to remedy this.
In EP-A-207904 there is described a covering sheet for covering an absorbent body of an absorbent sanitary article, the said structure having perforations which extend therethrough and comprising an upper layer intended to face outwardly of the absorbent body and comprising a non-woven fibrous material, an intermediate layer comprising a film, and a lower layer intended to face inwardly towards the absorbent body and comprising a non-woven fibrous material. It has been found that an elastic topsheet can be made following a modified form of the teachings of EP-A-207904, replacing the intermediate layer used therein with an elastic film. This is surprising, since the process for joining the three layers together would have been expected, prima facie, to result in the elastic film no longer being able to exhibit its elastic properties, as a result of its connection on both sides to the fibrous layers. However, it has been found the process described in EP-A-207904 can be modified so that it does not in fact have this effect. The modification has the effect that the upper and lower layers are connected to the intermediate layer substantially only around the perimeters of the perforations, and this permits the elastic film to continue to exhibit its elasticity in at least one direction.